A Vortex Damping Outflow Forcing for Multiphase Flows with Sharp Interfacial Jumps
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Outflow boundaries play an important role in multiphase fluid dynamics simulations involving low Weber numbers and large jump in physical variables. Inadequate treatment of these jumps at outflow generates undesirable fluid disturbances within the computational domain. We introduce a forcing term for incompressible Navier-Stokes equations that is coupled with a fixed pressure outflow boundary condition to enable stable exit of these disturbances from the domain boundary. The forcing term acts as a damping mechanism to control vortices that are generated by droplets/bubbles in multiphase flows, and is designed to be a general formulation that can be applied to a variety of fluid-flow simulations involving phase transition and sharp interfacial jumps. Validation cases are provided to demonstrate applicability of this formulation to pool and flow boiling problems, where bubble induced vortices during evaporation and condensation can lead to instabilities at outflow boundaries that eventually propagate downstream to corrupt numerical solution. Computational experiments are performed using , which is a composable open-source software instrument designed for multiscale fluid dynamics simulations on heterogenous architectures.
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